Mass spectrometry is an analytical technique that ionizes chemical species and sorts the ions based on their mass to charge ratio. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures.
In general, a mass spectrum is a plot of the ion signal intensity as a function of the mass-to-charge ratio. These spectra are used to determine the elemental or isotopic signature of a sample, the masses of particles and of molecules, and to elucidate the chemical structures of molecules, such as peptides and other chemical compounds.